HITCHCOCK GEASSES OF CUBA. 189 



Series Poaceae. — Spikelets 1 to many-flowered, the imperfect or rudimentary 

 floret, if any, uppermost; rachilla articulated (except in Oryzeae) above the ghimes, 

 which are persistent on the pedicel or rachis after the fall of the florets; when 2 to 

 many-flowered a manifest internode of the rachilla separating the florets and articu- 

 lated below them; spikelets laterally compressed. 

 Spikelets articulated below the glumes. (Oryzeae.) 

 Spikelets unisexual, plants moncKcious. 



Spikelets in pairs, one large, perfect, sessile, the other small, staminate, long- 

 pediceled; the broad oblanceolate blades with transverse veins between 



the longitudinal nerves. 45. Pharus (p. 234). 



Spikelets not in pairs, the staminate and pistillate in different panicles; 



blades linear, not cross-veined 46. Luziola (p. 234). 



Spikelets all perfect. 



Glumes wanting, lemma awnless 48. Homalocenchrus (p. 234). 



Glumes present. 



Glumes minute, awnless; lemma awned except in cultivated forms. 



47. Oryza (p. 234). 

 Glumes about as long as the floret or longer, awned. 



Glumes tapering into awns; spikelets, including awns, over 3 cm. 



long 49. Achlaena (p. 235). 



Glumes awned from the notched apex; spikelets, including awns, 



scarcely 1 cm. long 50. Reynaudia (p. 235). 



Spikelets articulated above the glumes. 



Culms woody, perennial, at least at the base, leaf blades commonly articulated 

 with and deciduous from the sheath. (Bambuseae.) 



66. Arthrostylidium (p. 245). 

 Culms herbaceous, annual, leaf blades not articulated with the sheath. 



Inflorescence of 1-sided spikes or racemes, spikelets sessile or nearly so. 

 (Chlorideae.) 



Plants dioecious or monoecious, the staminate awnless, pistillate with 



numerous awns; low stoloniferous grass 60. Opizia (p. 242). 



Plants not dioecious, spikelets all alike. 



Spikelets with 1 perfect floret, sometimes 1 or more sterile florets 

 above the perfect one. 



No sterile florets, spikelets awnless, spikes slender, digitate. 



54. Capriola (p. 238). 

 One or two sterile florets above the perfect one, spikelets gen- 

 erally awned. 

 Spikes digitate or approximate in apparent whorls at the 



summit of the culm 55. Chloris (p. 238). 



Spikes remote along the main axis. .56. Bouteloua (p. 240). 

 Spikelets with 2 or 3 perfect florets. 



Spikes alternate, more or less remote along the main axis, spike- 

 lets not crowded 59. Leptochloa (p. 241). 



Spikes digitate or nearly so, spikelets crowded. 



Axis of spike not produced beyond the uppermost spikelet, 



glumes and lemmas not cuspidate. . .57. Eleusine (p. 241). 



Axis of spike produced into a naked cuspidate point, glumes 



and lower lemmas cuspidate. 58. Dactyloctenium {ip. 241). 



Inflorescence paniculate, sometimes contracted but spikelets never sessile in 



1-sided spikes. 



Spikelets 1-flowered. (Agrostideae.) 



Lemma awnless 53. Sporoholus (p. 237). 



